package com.hc.model.code03.test2;

/**
 * @version v1.0
 * @ClassName: Computer
 * @Description: 电脑类
 *      电脑类只能读取SD卡中的数据
 * @Author: HC
 */
public class Computer {

    // 从SD卡中读取数据
    public String readSD(SDCard sdCard) {
        if (sdCard == null) {
            throw new NullPointerException("sd card is not null");
        }
        return sdCard.readSD();
    }


}
